Sectional articulated floating platform



Aug. 21, 1951 Filed Oct. 26, 1945 R. M. HAMILTON SECTIONAL ARTICULATEDFLOATING PLATFORM 6 Sheets-Sheet 1 Fon q /a M Ham/772 1 Aug. 21, 1951 R.M. HAMILTON ,3

SECTIONAL ARTICULATED FLOATING PLATFORM Filed 00p 26, 1945 6Sheets-Sheet 2 R. M. HAMILTON SECTIONAL ARTICULATED FLOATING PLATFORMAug. 21, 1951 6 Sheets-Sheet 5 Filed Oct. 26, 1945 lllll lllllll @2411'iiaw mu IHHHIHIHHHHI 24 Hllu Rona/d M Hqmf/fon /n ven 1'0! Aug. 21,1951 R. M. HAMILTON SECTIONAL ARTICULATED FLOATING PLATFORM v 6Sheets-Sheet 4 Filed Oct; 26, 1945 lllll'll'llulllllllul' lllullllllllllI Rona/d M Hamil/ n A /nven7'or M A m Aug. 21, 1951 R. M. HAMILTONSECTIONAL ARTICULATED FLOATING PLATFORM 6 Sheets-Sheet 5 Filed Oct. 26,1945 R nald M- Hanoi an /n venl'or Aug. 21, 1951 R. M'. HAMILTONSECTIONAL ARTICULATED FLOATING PLATFORM 6 Sheets-Sheet 6 Filed Oct. 26,1945 H To mflmfl m n find |I.M

. PM L mm? E W F E ml Th w H 3" mm? a E mm m! 2 4 fl analogous purpose.

Patented Aug. 21, 1951 SEGTIONAL. ARTICULATEDl FLOATING PLATFORM RonaldMarsden Hamilton, Farnham, England,

assignorto H'amiltons Lilyflex Surfaces Limited, London, England, aBritish company Application October 26, 1945, Serial No. 624,662 InGreat Britain May 28, 1941 '8: Claims.

1 This invention comprises improvements in or relating to floatingairfields, runways, bridges and the like, and is in part a continuationof my application Serial No. 476,462, filed February 19, 1943- whichhas, since the filing of this applicati'on matured into Patent No.2,527,995. It is an object of this invention to provide an improvedfloating platform which can be used as a runway for aircraft orafloating bridge or other The invention comprises a floating airfieldconsisting of blocks of polygonal formation which are fitted together soas to form a mosaic floor capable of floating" on the surface of waterand able to yield under the weight of aircraft or other vehicles locatedupon it so as to spread the load, to enable the structure to ride easilyover large waves and to afford a dynamic buoyancy to vehicles upon itwhen they are in motion over its surface. Bydynamic buoyancy is meantthat the progressive displacement of the water, caused by displacementof the depression in the surface of the structure when a vehicle ridesforward over it, produces an upward force on the structure due to theinertia of the water'which prevents the depression from being so deep asit would need to be if the vehicle were at rest.

The present invention further comprises a mosaic floating structurewherein the mosaic ele ments are united to one another by hingeconnections disposed around each mosaic element in positions where itadjoins its neighbours in such manner that the hinge-lines of the hingesextend in a plurality of intersecting directions.

Preferably the hinge-lines of the various sections are suchthat theyform a zig-zag pattern in every direction across the structure. Theobject of this is that there should be no direction in which thestructure as a whole is capable of bending in a straight line about itshinges because if such is the case the bending will be easier about sucha line than about other lines and the structure may be liable to take upa sharply bentor furrowed formation when waves come upon it from adirection at right angles to the line-along whichit bends most easily.For example the elements of the structure may be composed of regularhexagons so that the hinge lines extend across the structure in a seriesof zig-zagtracks the successive sections of which lie at angles of 120-to one another.

Such hexagonal or like structure, across which the hinge-lines formzig-zag patterns, although all the elements are hinged to one another,does not yield'to a load upon it by bendingabcut. one

axis or into a merely cylindrical shape. The

load tends to cause a depression like a very flat inverteddome, but asthe area of the surface of the depression is necessarily greater than 5the area of a flat surface of equal size as viewed in plan, the tendencyis to pull the units of the mosaic which are near the periphery inwardsto supply the extra area. As the units are very rigid this can only takeplace to a slight extent and therefore the depression is very flat andthe load which is located in the centre of, and is the cause of, thedepression is supported by a reaction spread over a large area of water.Even although the hinge joints may run, as 1above described, alongzig-zag lines, the structure as a whole is capable of bending into amore or less cylindrical or sinusoidal shape of large radius under theinfluence of large waves. If the hinge-lines run in straight: linesacross the structure and the direction of movement of the waves isatright angles tothe hinge-lines of course the sinusoidal configuration iseasily obtained and may become too sharp under theseconditions but withthe preferred construction in which the hinge-lines do not extend instraight lines but in zig-zag lines, a sinusoidal configuration of largeradius may be acquired by the structure on account of slight play in thehinge joints which is inevitable in manufacture, or which can be assuredif necessary by special design. In the case of the zig-zag pattern theadvantage is gained that the readiness to assume a sinusoidalconfiguration on the part of the structure is equal, or more or lessequal, for Waves coming from every direction.

A hexagonal formation has been referred to as preferable, and this isparticularly so because all the units of the mosaic may then be alike.However, mosaics built'up of sections of a plural- 40 ity of shapes,such as octagons interspersed with squares set diagonally, can beadopted with success, but they involve greater trouble in manufacture.

Preferably each of the mosaic elements is 4.5 designed to have afreeboard greater when it is floating unloaded than the depth of thedepression produced in the structure, under normal conditions of use, bythe load of the vehicles to be used thereon. If this .is done it isunnecessary to make the joints between the individual elements of themosaic watertight.

The hinge connections between the sides of each mosaic element and itsneighbours may be such as to permit twisting of the elementout of theplane of its neighbour, if desired, such twisting being limited by shockabsorbing devices.

The shock absorbing devices take the form of stops with means to cushionthe shock before the stops come into play.

Notwithstanding the quality of the structure explained above whichlimits the curvature of bends due to the hinge lines running in zigzagformation across the structure, it is desirable for structures which areto be used in choppy seas to provide means which further limit thecurving of the surface under the influence of waves and to do thiswithout unduly stressing the structure or losing the advantages derivedfrom its flexibility and the provision of shock absorbing devices asjust described is beneficial.

The invention includes, in a mosaic floating structure, the combinationof a mosaic formed by interfitting floating elements, hinge connectionsdisposed around each mosaic element in positions where it adjoins itsneighbours to unite the elements together, the hinge-lines extending ina plurality of intersecting directions, and damping devices alsointerconnecting the mosaic elements to retard bending of the hingesunder stress of wave forces. The damping devices may be of the hydrauliccylinder-and-piston type.

When the hinge-lines extend in zig-zag pattern in every direction acrossthe structure, the damping devices may consist of hydrauliccylinder-and-piston damping elements each positioned beneath a hingewith its line of extension parallel, or almost parallel, with the lineof the hinge.

It is possible for the damping devices to lie parallel, or almostparallel, to the lines of the hinges because flexing of the hexagonalstructure necessarily involves not only hinging about the axes of thepins but a certain amount of transverse movement of the pins in theirhinges and twisting of the elements relative to one another, since thepins, as above pointed out, do not anywhere extend across the structurein a straight line,

The following is a description by way of example of certainconstructions of floating structure in accordance with the invention,reference being made to the accompanying drawings, in which:

Figure 1 is a planof a part of the structure as assembled;

Figure 2 is a side elevation of one mosaic unit of the structure shownin Figure 1;

Figure 3 is a section upon the line 33 of Figure 2 looking downwards inthe direction of the arrows;

Figure 4 is a section upon the line 44 of Figure 2 with parts omittedlooking upwards in the direction of the arrows so that the underside ofthe deck is seen;

Figure 5 is a detail section through the joint between two mosaicelements showing the hinge connection in elevation;

Figure 6 is a plan of the same parts as are shown in Figure 5;

Figure 7 is a detail of the hinge pin;

Figure 8 is ,a longitudinal section through a shock absorbing unit;

Figure 9 is an end elevation of the same;

Figure 10 is a detail of an adjusting tool;

Figures 11 to 15 inclusive show an alternative construction originallyshown in the aforesaid United States Patent Application Serial N0476,462; in these figures:

Figure 11 is an underside plan view of a. floating airfield structure;

Figure 12 is a section on the line l2-l2 of Figure 11;

Figure 13 is a, diagram showing the method of construction of the partsused in Figures 11 and 12;

Figure 14 is a section through a modified construction, and

Figure 15 is a detail of the construction illustrated in Figure 14.

Referring first to Figures 1-10, floating structure consists of a. largenumber of hexagonal units each of which comprises a hexagonal deck plateII. The deck plates are shown in the drawings as flat but they may beprovided on their upper surface with some form of roughening orupstanding ribs or strakes not shown in the drawing, to prevent'slippingof the wheels of vehicles usin the surface. Alternatively the plates maybe corrugated, which has the advantage of stiffening them as .well as ofproviding a non-slipping surface.

To the underside of each of the plates I I there is welded a hexagonalfloat chamber the walls of which are indicated in Figure l by the dottedlines I2. The walls 12 are shown in full lines in Figures 2, 3 and 4 andthe chamber will be hereinafter referred to as the fioat chamber 12. Thebottom of the float chamber is closed by a hexanogal plate l3 (Figure 3)and this plate is stiifened by ribs [4 which extend across it in a,triangular formation and by a small triangle of ribs [5 uniting the ribsl4 together. The ribs l4, l5 are welded to the outer walls [2 of thefloat chamber and the walls 12 are also welded together at the cornersas wellas being welded to the deck plate II. .Each of the float chamberscomprises stiffening ribs [6 beneath the deck plate which are seen inthe underside section, Figure 4, and which extend radially, or nearlyradially from points slightly offset from the centre, toward the sidewalls and are welded to each other at the centre, to the side walls attheir ends and to the deck plate along their upper edges. Beneath theribs [6 where they meet one another at the centre there is welded acircular plate ll which unites them all more firmly together andtransmits tension from each rib to the opposite one. This structurestiffens the deck plate sufliciently to bear the load.

It will be noted that the deck plate ll overhangs the walls of the floatchamber l2 all round and that the deck plates .of the various elementsof the structure fit together with only a slight space between them. Thedeck plates H may measure say about six or seven feet between oppositesides and the spaces between their edges may be say half an inch to aninch in width. The thickness of the plates is such that they normallyfloat immersed to about one-third or half their depth, that is to sayabout eighteen inches or less in the water and they are thereforecapable of sinking substantially under load before becoming flooded overthe upper surface.

Taking the deck plate H, as seen in Figure 1, it will be observed thaton three sides it is widely notched out, as shown at l8, I9, 20, and onthe intervening sides it has narrower notches 2|, 22, 23. There projectfrom the element in the centre of the wide notches male hinge members 24and on each side of the narrow notches there project hinge members 25 ofthe corresponding female parts. The female hinge members on one of theplates H are adapted to fit with the male parts of hinge members onadjoining plates and by arranging the male and female partsalternatelyaround the sides ofthehexagon it will be found that all thehexagons will fit together and all be alike. The details of the hingesare hereinafter described. I v

In addition to the units being connected together by hinges, one in thecentre of each side, as just described, they are further connected byhydraulic piston-and-cylinder damping mechanisms with stops, whichmechanisms are located just above the plane of the bottoms of .the floatchambers. In Figure'l. the centre lines of the dampers are shown by thechain lines 26 and these dampers are constructed so that they resistboth extension and compression as hereinafter explained. It will benoted that there is a damper connecting each side of each unit with itsneighbour. Before-theparts are assembled the dampers are stowed on theunits, three to a unit, and occupy alternate sides. Theneighbouringunits supply the dampers to fill the .sides which do not carry thembefore assembly. In the drawing, Figure 2, a damper 30 is shown in thestowed position on one of the sides l2 while the two neighbouring sidesare shown without dampers. The damper 30 as stowed has been omitted fromFigure 4 but the three dampers are shown in situ in Figure 3 in thestowed position.

Before describing the damping means it is preferable to describe thehinges-inv some further detail. As can be seen from Figure 2. and Figure5 the male part 24 of the hinge is formed. from a flat steel bar whichis bent twice into a rectangular U-shape, the arms-0f the U being joinedtogether by a cross-piece 3| so that a square opening is left betweenthe cross-piece 3| and the bent part of the U-shaped bar. Thecross-piece is welded to the sides of the U and the U-shaped memberitself is turned over with the arms horizontal and welded at 32, 33 tothe wall l2 of the float chamber. A packing piece 34 is inserted betweenthe upper sides of the hinge 24 and the deck H and theU-shapedhingemember 24 is welded to the packing piece 34, the packingbeing itself welded to the deck. A triangular plate 35 welded to thewall of the float chamber l2 underlies the lower arm of thehingemember.and is welded thereto. A small packing piece 36 is welded to the top ofthe hinge member 24 to bring the upper surface up to-the level of thedeck.

On the female side the hinge comprises four upright plates 25 whichunderlie the overhanging edge of the deck II ofthe. next unit and arewelded thereto and to the wall I2. The plates 25 lie two to one side andtwo to the other side of the male member 24 of the hinge and theirattachment to the hexagonal unit is stiffened by means of a web plate 31which underlies them and is welded to them and to the wall I2. Theoutline of the plate 31 can be seen in dotted lines in Figure 6. Here itmay be observed that inthe drawings the fillets of the welds are notshown, to avoid cumbering the. drawing but their existence will beobvious to an engineer. Where the plates 25 project beyond the edges ofthe deck plates I I they are covered with packing pieces 38 to providean upper surface level with the deck surface and prevent any undue breakin the continuity thereof.

The plates 25 are pierced with openings to receive bushes 39, [39 whichfit the-end portions of a hinge pin and the hinge pin 40 is made 6square in cross-section at its middle portion so as. to fit the squarein the centre of the male hinge member 24. As can be seen from thedetail,

. Figure '7, the pin comprises a large end 4| which fits the bush 39, asquared central-portion 42 to fit the male member of the hinge and areduced circular portion 43' to fit the bush I39. The central. squaredportion 42 has flat faces on its vertical sides but is slightlybarrel-shaped on its upperv and lower sides as indicated at 44, 45 inFigure 7, so that it can permit a slight canting of one-half of. thehinge relatively to the other and thereby permit of any unit beingtwisted in its plane relative to the unit to which it is hinged. It willbe noted that. the squared portion is not a complete square but a squarewith rounded corners. On one end of the hinge pin there is an eye 46 forattachment to a chain by which it may be secured to the underside of thedeck plate. The chain is not shown in the drawing but it serves toprevent the hinge pin from being withdrawn from the bush 39 andaccidentally dropped in assembling the parts, because it would then fallinto the sea and be lost, but the chain is. long enough to permit thepin to be withdrawn so far as. to permit introduction of the male hingemember 24 between the two bushes. A locking pin 41 is provided which canbe dropped into a hole through the deck and fall in behind the head 4|of the pin 40 after it has been inserted in the hinge and thus preventit from working out again.

One of the dampers 30 is shown in Figures 8 and 9. It comprises a metaltube which forms the cylinder and is closed at one end by a cover plate50 welded to the cylinder and carrying an eye 5!. Within the cylinderare two pistons 52, 53 held apart by a strong buffer spring 54. Thepiston 52 which lies nearer to the cover plate 55 has a centralrecess 55and is bored centrally to pass a piston rod 56 which is capable ofsliding through the piston 52 into the recess. Within the recess the rod56 carries a screwed-on head 51. At the other end of the cylinder therod 56 passes through the piston 53 and is screwed into a sleeve 58. Thesleeve 58 is a sliding fit in a cover plate 59 which is welded in thecylinder after the other parts have been assembled. The sleeve 58 buttson the inside of a recess formed in the piston 53 and thus the spring 54is held compressed between the sleeve 58 on the rod 56 at one end andthe head 51 screwed on the rod at the other. An

eye 69 is screwed into the sleeve 58 and thus tension orcompression canbe applied to the damper 30 by applying force to the eyes 5!, 69. Ifcompression is applied the sleeve 58 is forced into the cylinder andpresses the piston 53 to the right as viewed in the figure, the amountof the movement permissible being that which suffices to bring the head51 against the cover plate 59 which acts as a stop. If tension isapplied the rod 56 draws the piston 52 to the left, as viewed in thefigure. This movement is limited by a tube 6! which is slid over the rod56 and is long enough to butt at the end of the desired movement againstthe piston 53 and so act as a stop.

Each of the pistons 52, 53 is provided with a single split piston ring62. In the centre of the cylinder 30 at the upper side there is a bleedhole '63 and at each end on the underside are bleed holes 64, 65.

have holes to receive the heads which are also countersunk but to awider angle than the angle of the heads of the screws. The bottoms ofthe countersunk holes in the clack valves being made of slightly greaterdiameter than the screws, it is impossible for the screws to grip thevalves tightly. The valves therefore hang against the insides of thecover plates 51], 59, the valve 66 serving to close an inlet port 69 andthe valve 61 to close an inlet port 70. The effective length of thedamper can be adjusted by rotating the sleeve 58 relatively to the eye60 and in order to facilitate this adjustment when the damper is insitu, the end of the sleeve 58 is cut into gear teeth H which areadapted to mesh with teeth [2 on an adjusting tool which consists of adisc 73 and an operating rod 14. The tool is shown in perspective inFigure 10 and it will be seen that the rod 14 carries a cross handle 75at the top. The disc 13 is pierced with an elongated hole I16 havingparallel sides and rounded ends and the distance between the sides ismade equal to the diameter of the pin 16 which enters the eye Eli.Therefore the length can be adjusted by slipping the disc 13 over thepin 75 and meshing the teeth 12 with the teeth ll, after which by givingthe disc a series of partial rotary movements alternatedwith lifting itoff the teeth H, moving it angularly back to its original position andremeshing, the sleeve 53 can be adjusted a few teeth at a time until thecorrect length is reached.

These dampers are fitted over upstanding pins 16 which are supported bybracket plates 1'! standing out from the underside of the float chamber[2, as can be seen in Figure 3. There is a bracket and an upstanding pin76 from each corner of the float chamber but prior to assembly there aredampers secured on three only of the pins 16. As can be seen fromFigures 2 and 3 the other ends of these dampers are temporarilysupported on bracketed pins 78 close below the male portions 24 of thehinges. In order to prevent the eyes 69 from sliding down the pin 16 theshank of the eye is supported on a short vertical plate bracket 79.

When two of the hexagonal elements are brought together, after the hingehas been pinned up, a hook is lowered through the space between theedges of the deck plates H and the eye 5| is lifted oiT the pin '18 andtransferred to the pin 16 of the next element, which will be found to bein position to receive it. This will swing the damper from the positionshown in Figure 3 where its axis is parallel to the side wall [2 of thefloat chamber into the position indicated in chain lines in Figure 1where its axis lies at an inclination to the axis of the hinge althoughrunning more or less parallel therewith. The slight swinging movementthus imparted to the damper serves to carry the shank of the eye 60clear of the bracket 19 and as a result the damper can slide down thetwo pins E5, the one on one of the hexagonal elements and the other onthe other element until it rests on the plates 1'! at the bottom of thepins.

If in assembling it is found that the length of the dampers does notquite fit, this can be adjusted by the tool shown in Figure 10, and thedampers can moreover, after having been as-- sembled and brought to thebottom of the pins 16, be further adjusted should this be foundnecessary, so that they are all more or less equally loaded when thestructure is flat.

The pins 16 stand up considerably away from the brackets 11 which carrythem and therefore are liable to become bent if they are given anaccidental blow in transit or in assembly. To guard against this tubeshaving flanged heads Bl are dropped through hqlesin the deck plates l Iso that they slide telescopically over the upper ends of the pins 16. Inassemblying the elements the tubes 80 need to be lifted off those pinson to which the eyes 5| are to be dropped, and after the dampers havesunk into place the tubes 80 are replaced.

It will be apprehended that the dampers 3B are stowed, when in theposition shown in Fi ure 5, somewhat above the water level. When, in thecourse of assembling, which is done afloat, the dampers have beentransferred at the eyes 5| on to the pin 16 and begun to sink toward thebottom of the pins, they do so quite slowly and gently as they more orless float down through the Water and during this time they fill withwater through the inlet valves 66, 81. Air bubbles out through the bleedholes 63 and in a short time the damper will be found to be full ofwater, in which condition it is ready for work.

The rate of leakage of water past the pistons and through the bleedholes is settled by the size of the bleed holes and by the clearancebetween the ends of the split piston ring 62 and this, in conjunctionwith the force exerted by the spring 54, gives a maximum total forcewhich the damper will exert. This force must be arranged to be withinthe strength of the hinges and the walls of the floating hexagonalelements and as a result the elements are held with their decks nearlylevel against all forces exerted by the waves up to that predeterminedby the spring 54 and they are permitted by the damper to flex slowlyagainst forces in excess of this figure. Thus the structure can never beoverstrained and always keeps itself as flat as its strength willpermit.

In the event of a heavy storm it may be that sections of the structurecannot flex sufiiciently fast to prevent the structure from being liftedby the waves so that a portion of it will bridge between the crests ofadjacent waves. In such a case the dampers when they rise above thesurface of the'sea will rapidly empty themselves and their dampingaction will therefore be automatically eliminated, at all eventstemporarily, so that the structure will be more easily accommodateitself to rough waves. As a floating aerodrome or pier of this kindcannot be used in a storm it is a distinct advantage that under suchconditions it accommodates itself to the waves more easily and is lessstressed than when it is riding fully awash in calm weather. Thestructure will maintain a surface fiat enough for aircraft to alightupon in all weathers up to a certain degree of violence of the waves,above which it will not be usable but will, if properly constructed, beable to ride out the storm.

The cylinders empty partly through the clack valves, which hang ratherloosely at those ends of the cylinders where there is no pressure, andso emptying is more rapid than filling, which latter is limited by therate of escape of air through the single small hole at the middle of theupper side. Therefore it will be appreciated that in stormy weatherthere will be a general tendency to keep a certain amount of air in thedamping cylinders which reduces the stiffness of the structure but asthe weather moderates the stiffness will automatically return.

Referring now to Figures 11 to 13 these show a construction of floatingfloor for an aerodrome.

. ,o'or'isshown. It c s s s of a lar e numb r for asonal pieces o WooThese m ybea' ttwo inch s hick n they each 'carryIbeneath" them astern-portion 9| made of two .triangularblocks of wood of similarthickness secured to theyhead 9.0 b means of a bolt 92 and nut 93. Thesehexagonal uni s r l held to ether by m sh of wir s 94', 95, 96 on theirunderside, which mesh is constituted by thiee alfiallel sets of wirescrossing one another at angles of 60 degrees and united at each crossingpointby the boltsand nuts 92, 93. The wiresfare all stranded wire'andare par ly u anded a dley lett d Wh re they as o er th bolts u h "aconst uction can be exn e as r s'desi ed n any d recti and t e wires 5can. be mad i'up in l ngths which cover a certain number ofsect1ons,'with on ise t i o as an y a eac end, an h n co m again ifnecessary. Such" a structure being mainly constructed of wood, willfloat of itself and as the hexagonal'sections' fit closely together andare prevented from moving apart by the wire mesh beneath them, it willonly bend downwards, when a weightisiplaced upon it, with a somewhatslight radius of curvature. In other words the structure is stiffenedsufficiently to spread the load although it"re mains flexible. Thereforeaircraft can be launched across the surface and the Weight of theaircraft is distributed over a large area of water, the whole forming aflexible mat. Water-tightness between the sections can be assisted, ifdesired, by rubber J'OiHtSw lit i rictpqsitiv ly ess a .beea t e i h ofan a rcraf when-alightins o a in rests on any particular part of thefloor for a short period of time only. Around the edges of the aerodromethus created there would preferably be erected a barrier or fence ofcanvas of a height sufficient to prevent the surface from being swampedby waves.

Figure 13 shows how the hexagons 9B and the triangles 9| can be cut froma single plank by making criss-cross cuts at intervals. By manufacturingin this way waste of wood is avoided.

If it is important to save timber, a structure similar to that ofFigures 11 to 13 can be manufactured of moulded material such asconcrete by using hexagonal mushroom shaped elements I00, as shown inFigures 14 and 15, each of which is made of concrete and is bolted to awire mesh structure Nil beneath it, this structure being similar to thatshown in Figure 1, (it will be borne in mind that Figure 11 is a viewlooking upwards from the underside). Below the wire mesh there is alayer of canvas IE2, the edges of which extend upwardly around the sidesof the aerodrome, as shown at I03. The canvas I62 is made in hexagonalsections and each section is bent up at the joints between the sections,as shown at I04, so that the sections are self-contained. In this way anaerodrome is built up of a large number of floating hexagonal sections.The edges will be somewhat irregular as they will follow the hexagonallines, but they can be filled in, if desired, by semi-heXagons. Aroundthe edges is an upstanding concrete wall I05.

It will be noted that one feature of the aerodrome surface described, isthat the structure as a whole is not likely to be severely damaged by abomb on any one part as the bomb will naturally pass through beforeexploding and the purely localised damage which would result, could berapidly repaired by fresh sections.

I claim:

1. A floating structure comprising, in combination, a number of buoyantsections each having a deck, the decks fitting together as a mosaic andbeing of such shape that the joints between the several sections of themosaic extend across the mosaic in zig-zag courses and nowhere proceedfrom between one pair of sectionsto between another pair in a straightline, hinges connecting the adjacent sides of the decks, said hingeshaving their axes parallel with the sides of the decks which theyconnect, means associated with each hinge afford limited relativeangular movement of the sections at the hinge at right angles to thehinge axis, and means located'below the deck level between the sectionsan'd'intercon'nected from each section to its neighbors, to limit theangular movements of the sections relatively to one another.

2. A floating structure comprising in combination, a number of buoyantsections each'having a hexagonal deck, the decks fitting together as amosaic, hinges connecting the adjacent sides of the decks, the saidhinges having their axes parallel with the sides of the decks which theycorinect, means associated with each hinge which afford limited relativeangular movement of the sections at the hinge at right angles to thehinge axis, and means located below the deck level between the sectionsand interconnected from each section to its neighbors, to' limit theangular movements of the sections relatively to one another.

3. A floating structure comprising, in combination, a number of buoyantsections each havi a deck, h de k fi n o ethe as am s i nd bei o suc aptha t fioi tsbetwe the several sections of the mosaic extend across themosaic in zig-zag courses and nowhere proceed from between one pair ofsections to between another pair in a straight line, hinges at decklevel connecting the adjacent sides of the decks and having hinge-axesparallel with the sides which they connect, means associated with eachhinge which affords a limited relative angular movement of the sectionsat the hinge at right angles to the hinge axis, and hydrauliccylinder-and-piston type shock absorbing means each of which is jointedat one end to one section and at the other end to an adjacent section ata level below deck level such that they operate submerged, said shockabsorbing means serving to limit the angular movement of the sectionsrelatively to one another.

4. A floating structure as claimed in claim 3, wherein the line ofextension of each shock absorbing element is substantially parallel withthe line of the hinge located at deck level above it.

5. A floating structure comprising, in combination, a number of buoyantsections each having a hexagonal deck the decks fitting together as amosaic, hinges at deck level connecting the adjacent sides of the decksand having hinge-axes parallel with the sides which they connect, meansassociated with each hinge which afford a limited relative angularmovement of the sections at the hinge at right angles to the hinge axis,the hydraulic cylinder-andpiston type shock absorbing means each ofwhich is jointed at one end to one section and at the other end to anadjacent section at a level below deck level such that they operatesubmerged, said shock absorbing means serving to limit the angularmovement of the sections relatively to one another.

6. A floating structure as claimed in claim 5,

11 wherein the line of extension of each shock absorbing element issubstantially parallel with the line of the hinge located at deck levelabove it.

7. A floating structure comprising, in combination, a number of buoyantsections each having a deck, the decks fitting together as a mosaic andbeing of such shape that the joints between the several sections of themosaic extend across the mosaic in zig-zag courses and nowhere proceedfrom between one pair of sections to between another pair in a straightline, hinges connecting the adjacent sides of the decks said hingeshaving their axes parallel to the sides of the decks which they connect,means associated with each hinge which afford limited relative angularmovement of the sections at the hinge at right angles to the hinge axis,and means to limit the angular movements of the sections relatively toone another comprising hydraulic damping elements, each consisting of acylinder, two damping pistons therein with a spring located betweenthem, a piston rod entering the cylinder from one end and extendingslidably through both pistons which piston rod carries, on the side ofeach piston further from the spring, a shoulder to engage behind thepiston, whereby the same spring acts to resist both extension andcompression of the shock absorbing element, the cylinder being connectedto one of the mosaic sections and the piston rod to an adjacent section.

8. A floating structure, comprising in combination, a number of buoyantsections each having a hexagonal deck, the decks fitting together as amosaic, hinges connecting the adjacent sides of the decks said hingeshaving their axes par- 12 allel to the sides of the decks which they connect, means associated with each hinge which afford limited relativeangular movement of the sections at the hinge at right angles to thehinge axis, and means to limit the angular movements of the sectionsrelatively to one another comprising hydraulic damping elements, eachconsisting of a cylinder, two damping pistons therein with a springlocated between them, a piston rod entering the cylinder from one endand extending slidably through both pistons which piston rod carries, onthe side of each piston further from the spring, a shoulder to engagebehind the piston, whereby the same spring acts to resist both extensionand compression of the shock absorbing element, the cylinder beingconnected to one of the mosaic sections and the piston rod to anadjacent section.

RONALD MARSDEN HAMILTON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Smith Oct. 14. 1890 Duncanson May 10,1910 Kulik Feb. 7, 1933 FOREIGN PATENTS Number Number

